Change intervention console messages from warnings to errors.

Since interventions actually block or change browser behavior, their
messages should be reported as errors rather than just warnings.

Bug: 564071
Change-Id: Id8f1110466f127903bd362c4c7ada454aa3df0d6
Reviewed-on: https://chromium-review.googlesource.com/985028Reviewed-by: Nate Chapin <japhet@chromium.org>
Commit-Queue: Paul Meyer <paulmeyer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547896}

third_party/WebKit/LayoutTests/fast/events/touch/touch-action-preventDefault-expected.txt

-CONSOLE WARNING: line 13: Unable to preventDefault inside passive event listener due to target being treated as passive. See https://www.chromestatus.com/features/5093566007214080
+CONSOLE ERROR: line 13: Unable to preventDefault inside passive event listener due to target being treated as passive. See https://www.chromestatus.com/features/5093566007214080
 This is a testharness.js-based test.
 PASS Forced passive event listener
 PASS Forced passive event listener with touch-action

third_party/WebKit/LayoutTests/fast/events/touch/touch-event-cancelable-expected.txt

@@ -2,9 +2,9 @@ CONSOLE MESSAGE: line 32: Sending cancelable touchmove
 CONSOLE MESSAGE: line 21: Calling preventDefault on TouchEvent with cancelable=true
 CONSOLE MESSAGE: line 39: Sending uncancelable touchmove
 CONSOLE MESSAGE: line 21: Calling preventDefault on TouchEvent with cancelable=false
-CONSOLE WARNING: line 22: Ignored attempt to cancel a touchmove event with cancelable=false, for example because scrolling is in progress and cannot be interrupted.
+CONSOLE ERROR: line 22: Ignored attempt to cancel a touchmove event with cancelable=false, for example because scrolling is in progress and cannot be interrupted.
 CONSOLE MESSAGE: line 64: Sending uncancelable touchmove
-CONSOLE WARNING: line 57: Ignored attempt to cancel a touchmove event with cancelable=false, for example because scrolling is in progress and cannot be interrupted.
+CONSOLE ERROR: line 57: Ignored attempt to cancel a touchmove event with cancelable=false, for example because scrolling is in progress and cannot be interrupted.
 This is a testharness.js-based test.
 PASS Test that touch events may or may not be marked cancelable. http://crbug.com/365681
 PASS Test that warning occurs in default mode

third_party/WebKit/Source/core/events/TouchEvent.cpp

@@ -261,9 +261,9 @@ void TouchEvent::preventDefault() {
   UIEventWithKeyState::preventDefault();
 
   // A common developer error is to wait too long before attempting to stop
-  // scrolling by consuming a touchmove event. Generate a warning if this
+  // scrolling by consuming a touchmove event. Generate an error if this
   // event is uncancelable.
-  String warning_message;
+  String message;
   switch (HandlingPassive()) {
     case PassiveMode::kNotPassive:
     case PassiveMode::kNotPassiveDefault:
@@ -285,17 +285,17 @@ void TouchEvent::preventDefault() {
                 WebFeature::
                     kUncancelableTouchEventDueToMainThreadResponsivenessPreventDefaulted);
           }
-          warning_message =
+          message =
               "Ignored attempt to cancel a " + type() +
               " event with cancelable=false. This event was forced to be "
               "non-cancellable because the page was too busy to handle the "
               "event promptly.";
         } else {
           // Non blocking for any other reason.
-          warning_message = "Ignored attempt to cancel a " + type() +
-                            " event with cancelable=false, for example "
-                            "because scrolling is in progress and "
-                            "cannot be interrupted.";
+          message = "Ignored attempt to cancel a " + type() +
+                    " event with cancelable=false, for example "
+                    "because scrolling is in progress and "
+                    "cannot be interrupted.";
         }
       }
       break;
@@ -304,7 +304,7 @@ void TouchEvent::preventDefault() {
       // an author may use touch action but call preventDefault for interop with
       // browsers that don't support touch-action.
       if (current_touch_action_ == TouchAction::kTouchActionAuto) {
-        warning_message =
+        message =
             "Unable to preventDefault inside passive event listener due to "
             "target being treated as passive. See "
             "https://www.chromestatus.com/features/5093566007214080";
@@ -314,10 +314,9 @@ void TouchEvent::preventDefault() {
       break;
   }
 
-  if (!warning_message.IsEmpty() && view() && view()->IsLocalDOMWindow() &&
+  if (!message.IsEmpty() && view() && view()->IsLocalDOMWindow() &&
       view()->GetFrame()) {
-    Intervention::GenerateReport(ToLocalDOMWindow(view())->GetFrame(),
-                                 warning_message);
+    Intervention::GenerateReport(ToLocalDOMWindow(view())->GetFrame(), message);
   }
 
   if ((type() == EventTypeNames::touchstart ||

third_party/WebKit/Source/core/frame/Intervention.cpp

@@ -25,7 +25,7 @@ void Intervention::GenerateReport(const LocalFrame* frame,
 
   // Send the message to the console.
   frame->Console().AddMessage(ConsoleMessage::Create(
-      kInterventionMessageSource, kWarningMessageLevel, message));
+      kInterventionMessageSource, kErrorMessageLevel, message));
 
   if (!frame->Client())
     return;